Re:C# 9 top-level programs and target-typed expressions
by Mindless2112 on Tuesday March 30, 2021 @07:30PM
(#26641836)
You can (and I do), but it is explicitly not supported. If it breaks, you get to keep both halves.
For the most part that isn't true. You can use later C# compilers with older frameworks. Some features do, unavoidably, require framework support.
But that being said, the changes in C# aren't often that radical that I feel particularly constrained by older versions.